Alarm for combination-locks.



F. R. McNABB & R. M. SKINNER,

ALARM FOR COMBINATION LOCKS.

APPLICATION mu) IULY 31.1916.

1,269,542. PatentedJune 11, 191

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UNITED STATES PATENT OFFICE.

FLOYD IR. MONABB AND RICHARD M. SKINNER, OF SAN FRANCISCO, CALIFORNIA.

ALARM FOR COMBINATION-LOCKS.

Specification of Letters Patent.

Patented June 11, 1918.

Application filed July 31, 1916. Serial No. 112,275.

To all whom it may concern:

Be it known that we, FLOYD R. MCNABB and RICHARD M. SKINNER, citizens of the United States, residing at San Francisco, in the county of San Francisco and State of California, have invented new and useful Improvements in Alarms for Combination- Locks, of which the following is a specification.

The present invention relates to improvements in alarms for so-called combina tion locks, the object of the invention being to provide a simple and inexpensive device which will cause an alarm to be sounded whenever the knob of the combination lock is turned too far in either direction.

In the accompanying drawing, Figure 1 is a front view of a combination lock having our improved alarm attached thereto; Fig. 2 is acentral vertical section thereof, certain parts being shown in side elevation; Fig. 3 is a rear view.

Referring to the drawing, 1 indicates an ordinary combination lock having a dial 2 and a controlling knob 3 connected to a shaft 4 for cooperating with the tumblers of the lock. Secured by screws 6 to the rear wall 7 of the lock, or, as an alternative construction formed integral therewith, is a plate 8 from which extend rearwardly two pillars 9, the rear ends of which are connected to a'vertical bridge'll. Said shaft 4 is extended rearwardly and its rear end is secured in said bridge by a screw 10. Surrounding the extension of the shaft 4 is a tubular screw 12, which is secured to said shaft 4, so as to turn with the dial 2, by a set screw 13 screwed through a head 14 of said tubular screw 12. Engaging said screw is an internally threaded traveler 16 having extensions 17 having apertures through which extend the pillars 9, said extensions traveling on said pillars. Extending horizontally from said traveler is a contact plate 18, which is adapted in the movement of the traveler, to contact with one or the other of two contacts 19 between which it is located, said contacts 19 being secured to threaded stems 21, which are adjustable in a slot 22 in a plate 23 extending rearwardly from a .vertical plate 24 secured by screws 26 to the plate 8 but insulated therefrom by insulating material 27 and insulating washers 28.

Said stems 21 are clamped in said slot at any desired point by means of clamping nuts 29 and washers 31. Upon the rear end of the plate 23 and upon the rear side of the plate 8 are secured binding posts 32, 33. These binding posts are connected to wires 34 leading to a source of supply of electricity and also to an audible alarm 37.

From the above description of the construction it will be understood that the traveler 16, and therefore the contact plate 18, move longitudinally, either forward or backward, with the turning of the knob 3 and shaft 4, and, if the turning movement of the knob is too great, the contact plate 18 will contact with one or the other of the contact plates 19, thereby closing the circuit between the two binding posts and actuating the alarm. Thus any person tampering with the combination lock, or trying to discover the combination, would be almost certain to actuate the alarm.

By unscrewing the set screw 13, the screw 12 can be turned on the shaft 4 so as to adjust the contact plate 16 longitudinally, whenever necessary.

1. In a circuit closer, a shaft, a support therefor, a screw secured to said shaft, an internally threaded traveler engaging said screw, means extending from said support for preventing the rotation of said traveler, a contact movable with said traveler, and a second contact adjustable in a direction parallel with the travel of said first-named contact, said contacts forming terminals of a circuit.

2. In a circuit closer, a shaft, :1 support therefor, a screw secured to said shaft, an internally threaded traveler engaging said screw, means extending from the support for preventing the rotation of said traveler, a contact movable with said traveler, two contacts electrically connected,- and between which the first contact extends, and adjustable in a direction parallel with the travel of said first-named contact, said first contact forming one terminal of a circuit and the.

other two contacts forming the other terminal thereof.

FLOYD R. MoNABB. RICHARD M. SKINNER.

copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, 20.. G. 

